I want to optimise the regex itself by making it more readable and "Compact". I searched on how to do that and I found something called back-reference, in which you can name your capturing groups and then reference them later as such:

Note that \g{N} is equivalent to \1, that is, a backreference that matches the same value, not the pattern, that the corresponding capturing group matched. This syntax is a bit more flexible though, since you can define the capture groups that are relative to the current group by using - before the number (i.e. \g{-2}, (\p{L})(\d)\g{-2} will match a1a).

The PCRE engine allows subroutine calls to recurse subpatterns. To repeat the pattern of Group 1, use (?1), and (?&Val) to recurse the pattern of the named group Val.

Also, you may use character classes to match single characters, and consider using ? quantifier to make parts of the regex optional: